Disproportionate exposure to traffic-related air pollutants among minority children with low socio-economic status is a major public health concern since it can contribute to perpetuate health disparities in the US. Children are particularly susceptible to the adverse health effects of air pollutants since they spend more time outdoors, have greater activity levels, lower tidal volumes and higher breathing frequency when compared to adults. These factors result in children receiving higher doses of pollutants per body weight. In addition, during childhood the CNS, immune and respiratory system are still in development. Exposure to traffic-related air pollutants have been reported to have respiratory and neurocognitive effects in children. Puerto Rican children already bear a disproportionate burden of respiratory conditions such as asthma and Hispanic children have the highest national prevalence of developmental disorders and functional limitations. For these reasons the main goal of the proposed research is to study the impact of traffic-related air pollutants in the development of lung function and neurocognitive impairments in Puerto Rican children. The specific aims of the study are: (1) examine the impact of living near two main sources of air pollutants in the lung function capacity of Puerto Rican children, (2) determine the impact of living near two main sources of air pollutants in neurocognitive development of Puerto Rican children, and (3) evaluate short- and long-term impact of environmental exposures in children lung function and neurocognitive processes. To this end we plan to conduct a longitudinal study in a cohort of Puerto Rican children living near two main sources of air pollutants. In addition, we will assess short-term variations in lung function capacity with variation in air pollutant concentrations. The relative risk of lung and neurocognitive impairment among children living near sources of air pollutants will be calculated using a binary logistic regression model controlling for possible confounding factors. Multivariate linear random effect models will be conducted to assess the relationship between air pollutants and lung function. To our knowledge, this will be the first study in Puerto Rico to assess such relationships. Through the proposed study we expect to: contribute to the advancement of health disparities research in the Puerto Rican/Hispanic population and to promote potential multidisciplinary collaborations to identify environmental factors during childhood impacting lung and neurocognitive development.